U.S. Pat. No. 7,360,447 B2 discloses an ultrasonic flow measuring device, in the case of which an acoustic signal is reflected by concave reflectors. There, the acoustic signals are transmitted parallel to the flow direction of the fluid.
An ultrasonic flow measuring device working according to the travel time difference principle is known per se and is described, for example, in German Patent DE 10 2011 079 250 A1 (US 2014144247). Such discloses an ultrasonic flow measuring device having a transmitter and a receiver, which are arranged in or on a measuring tube. The transmitter transmits an acoustic signal, which is reflected on one or more reflection surfaces and then strikes a receiver. This ultrasonic flow measuring device has basically done well. In the case of higher flow velocities, however, a lessening of the signal intensity is observed, since the acoustic signal is dispersed by the high flow velocity of the fluid and then is only partially registered by the sensor.